The present invention relates to systems of controlling operation of an internal-combustion engine of a motor vehicle, of the type comprising: one or more electronic control devices that affect the operation of the engine; sensor means for detecting the composition of the exhaust gases of the engine; and an electronic control unit that controls the operation of said electronic devices according to the signals at output from said sensor means.
In an internal-combustion engine of a motor vehicle with electronically controlled injection of petrol, the injector devices associated to the cylinders of the engine are controlled by an electronic control unit depending also, amongst the other parameters, upon the signals emitted by a sensor referred to as “lambda sensor”, which measures the content of oxygen of the exhaust gases. By means of experimental measurements, there have been established correlations between the concentration of oxygen and the concentration of the other gases present in the exhaust gases. The signal of the lambda sensor is set in a feedback loop which controls injection.
On the other hand, it should be considered that the interest for the environmental problems and, in particular, the impact of human activities on the environment has led, in the last few years, to the development of more and more stringent legal standards as regards the emissions in the exhaust gases of internal combustion engines of motor vehicles. The evolution of the injection technologies and the introduction of catalytic exhaust-pipe silencers has already reduced considerably the emission of noxious substances into the environment.